JP2021500603A - Forming multiple spatial images with a single lithography exposure pass - Google Patents

Abstract

A set of optical pulses of the optical beam passes through the mask and is directed at the wafer during a single exposure pass, and at least the first spatial image and a first spatial image on the wafer based on the optical pulses in the pulse set passing through the mask. Two spatial images are generated during a single exposure pass, the first spatial image is in the first plane on the wafer and the second spatial image is in the second plane on the wafer. The plane 1 and the plane 2 are spatially individual to each other and are separated from each other by a separation distance along the propagation direction to form a three-dimensional semiconductor component. [Selection diagram] FIG. 1A

Description

Cross-reference of related applications
[0001] This application claims the priority of US Provisional Patent Application No. 62 / 574,628 filed October 19, 2017, which is incorporated herein by reference in its entirety.

[0002] This disclosure relates to forming multiple spatial images in a single lithographic exposure pass. The techniques discussed below can be used, for example, to form three-dimensional semiconductor components.

[0003] Photolithography is a process of patterning a semiconductor circuit on a substrate such as a silicon wafer. The photolithography light source provides deep ultraviolet (DUV) light used to expose the photoresist on the wafer. DUV light for photolithography is generated by an excimer light source. In many cases, the light source is a laser source and the pulsed light beam is a pulsed laser beam. The light beam passes through a beam delivery unit, reticle or mask and is then projected onto a prepared silicon wafer. In this way the chip design is patterned on the photoresist, then etched and washed, and the process is repeated.

[0004] In one general embodiment, a method of forming a three-dimensional semiconductor component using a photolithographic system is to direct a pulsed light beam containing multiple light pulses toward a mask along the propagation direction. A set of light pulses of light beam is directed through the mask to the wafer during the exposure pass, on the wafer based on the light pulses in the pulse set passing through the mask during a single exposure pass. To generate at least a first spatial image and a second spatial image, the first spatial image is on the first plane on the wafer and the second spatial image is on the second plane on the wafer. Yes, the first and second planes are spatially separate from each other, separated from each other by a separation distance along the propagation direction, and the light of the first spatial image and the material of the first part of the wafer. Includes forming a three-dimensional semiconductor component based on the interaction with and the interaction of the light of the second spatial image with the material of the second portion of the wafer. The separation distance is increased by having at least one of the pulses in the pulse set having a first primary wavelength and at least one of the other pulses in the pulse set having a second primary wavelength different from the first primary wavelength. It is formed during a single exposure pass based on the difference between the first primary wavelength and the second primary wavelength.

[0005] The implementation can include one or more of the following features. At least one of the pulses in the pulse set passing through the mask during a single exposure pass can have two or more primary wavelengths of light.

[0006] Each primary wavelength may be separated by a spectral separation of 200 femtometres (fm) to 500 picometers (pm) from the nearest other primary wavelength.

[0007] The separation distance between the first spatial image and the second spatial image can vary during a single exposure pass.

[0008] The single exposure pass may be the first exposure pass, the method is further during the second exposure pass and after the first exposure pass is completed, the second of the light pulses of the light beam. It can include directing the set through the mask and towards the wafer. The separation distance between the first spatial image and the second spatial image differs between the first exposure pass and the second exposure pass.

[0009] The separation distance between the first spatial image and the second spatial image can be set prior to the single exposure pass, and in some implementations the separation distance is between the single exposure passes. It does not change. The separation distance between the first spatial image and the second spatial image can be set to adapt to one or more features of the photolithography system.

[0010] The pulse set includes a first group of optical pulses and a second group of optical pulses, each pulse of the first group of optical pulses having a first primary wavelength and a first group of optical pulses. Each pulse in the second group has a second primary wavelength, and the method further controls the amount of light in the first spatial image by controlling the characteristics of the first group of pulses, and the second of the pulses. Includes controlling the amount of light in the second spatial image by controlling the characteristics of the group of. The characteristic of the first group may be the number of pulses of the first group, and the characteristic of the second group may be the number of pulses of the second group. Controlling the number of pulses in the first group can include determining the number of first pulses included in the first group of pulses before the start of a single exposure pass, the number of second pulses. Controlling can include determining the number of second pulses included in the second group of pulses before a single exposure pass. The first group of pulses and the second group of pulses can include all pulses that pass through the mask in a single exposure pass. Determining the number of first and second pulses is to (a) receive input from the operator and (b) access the pre-defined settings associated with the photolithography system. It can include one or more. The characteristics of the first group of pulses can include the intensity of each pulse in the first group, and the characteristics of the second group of pulses can include the intensity of each pulse in the second group.

[0011] The first plane on the wafer and the second plane on the wafer may be planes that are substantially perpendicular to the propagation direction.

[0012] In some implementations, the first feature of the 3D semiconductor is formed in the first plane and the second feature of the 3D semiconductor is formed in the second plane, the first and second. The features are separated from each other by side walls that extend substantially parallel to the propagation direction.

The 3D semiconductor component may be a 3D NAND flash memory component.

[0014] The first plane may correspond to the first focal plane, the second plane corresponds to the second focal plane, and the separation distance between the first plane and the second plane is a mask. Based on the difference in wavelength of one or more of the light pulses passing through, or the difference in wavelength between the individual pulses of the pulse set.

[0015] In another general aspect, a photolithography scanner device comprising a light source, a mask and a wafer holder arranged to interact with a pulsed light beam from the light source, and a light source. The control system comprises a control system coupled to the light source to emit a pulsed light beam toward the lithography scanner device during a single exposure pass, at least during a single exposure pass. The first spatial image and the second spatial image are formed on the wafer supported by the wafer holder based on a set of optical pulses of optical pulses passing through the mask along the propagation direction, and the first spatial image is formed. Is on the first plane on the wafer, the second spatial image is on the second plane on the wafer, the first and second planes are spatially separate from each other and along the propagation direction. Separated from each other by a separation distance, the three-dimensional semiconductor components interact with the light of the first spatial image and the material of the first part of the wafer and the light of the second spatial image and the second portion of the wafer. It is formed based on the interaction with the material. At least one of the pulses in the pulse set has a first primary wavelength, and at least one of the other pulses in the pulse set has a second primary wavelength different from the first primary wavelength, the first. The separation distance between the spatial image and the second spatial image is based on the difference between the first primary wavelength and the second primary wavelength.

[0016] The implementation form can include one or more of the following features. The control system comprises a computer-readable storage medium, one or more electronic processors coupled to the computer-readable storage medium, an input / output interface, and recipes related to the photolithographic system are stored in the computer-readable storage medium. .. The recipe can specify the separation distance. The recipe specifies the separation distance for each wafer or lot. The light source can include a krypton fluoride (KrF) gain medium or an argon fluoride (ArF) gain medium.

[0017] Implementations of any of the techniques described above herein include processes, devices, control systems, instructions stored on non-temporary machine-readable computer media, and / or methods. It may be included. Details of one or more implementations will be revealed in the accompanying drawings and the following description. Other features will become apparent from the description and drawings, and from the claims.

[0018] It is a block diagram of an exemplary implementation of a photolithography system. [0019] FIG. 2 is a block diagram of an exemplary implementation of an optical system for the photolithography system of FIG. 1A. [0020] FIG. 6 is a cross-sectional view of an exemplary wafer exposed by the photolithography system of FIG. 1A. [0021] FIG. 6 is a block diagram of another exemplary implementation of a photolithography system. [0022] FIG. 3 is a block diagram of an exemplary implementation of a spectral feature selection module that can be used in a photolithography system. [0023] It is a block diagram of an exemplary implementation of a line narrowing module. [0024] A plot of data related to the generation of pulses and / or bursts of pulses at a light source. [0024] A plot of data related to the generation of pulses and / or bursts of pulses at a light source. [0025] FIG. 3 is a block diagram of another exemplary implementation of a photolithography system. [0026] A flowchart of an exemplary process for forming a three-dimensional semiconductor component. [0027] An exemplary optical spectrum of a single light pulse is shown. [0027] An exemplary optical spectrum of a single light pulse is shown. [0028] An exemplary average optical spectrum of a single exposure pass is shown. [0029] An exemplary wafer vertical cross section is shown. [0029] An exemplary wafer horizontal cross section is shown. [0030] A vertical cross-sectional view of an exemplary three-dimensional semiconductor component is shown. [0030] A horizontal cross-sectional view of an exemplary three-dimensional semiconductor component is shown. [0031] Illustrative simulated data is shown. [0031] Illustrative simulated data is shown.

[0032] In the present specification, a technique of forming two or more spatial images on different planes by a single lithography pass and a technique of forming a three-dimensional semiconductor component using this spatial image are considered.

[0033] Referring to FIG. 1A, the photolithography system 100 includes a light source 105 that supplies a light beam 160 to the lithography exposure apparatus 169, which processes the wafer 170 supported by a wafer holder or stage 171. To do. The light beam 160 is a pulsed light beam containing pulses of light that are temporally separated from each other. The lithography exposure apparatus 169 includes a projection optical system 175 through which the light beam 160 passes before reaching the wafer 170, and a metrology system 172. The metrology system 172 may include, for example, an image of the wafer 170 and / or light such as a camera or other device capable of capturing the light beam 160 on the wafer 170, or the intensity of the light beam 160 on the wafer 170 in the xy plane. An optical detector that can collect data describing the characteristics of the beam 160 can be provided. The lithographic exposure apparatus 169 can be an immersion system or a dry system. The photolithography system 100 can also include a control system 150 that controls a light source 105 and / or a lithography exposure apparatus 169.

[0034] For example, by exposing a layer of radiation sensitive photoresist material on a wafer 170 with a light beam 160, microelectron features are formed on the wafer 170. Further, referring to FIG. 1B, the projection optical system 175 includes a slit 176, a mask 174, and a projection objective system including a lens 177. The light beam 160 enters the optical system 175, collides with the slit 176, and at least a portion of the beam 160 passes through the slit 176. In the examples of FIGS. 1A and 1B, the slit 176 is rectangular and forms the light beam 160 into an elongated rectangular light beam. A pattern is formed on the mask 174, which determines which portion of the molded light beam is transmitted by the mask 174 and which portion is blocked by the mask 174. The design of the pattern is determined by the particular microelectronic circuit design that will be formed on the wafer 170.

[0035] The formed light beam interacts with the mask 174. A portion of the molded light beam transmitted by the mask 174 passes through the projection lens 177 (and can be focused by the projection lens 177) to expose the wafer 170. A portion of the molded light beam transmitted by the mask 174 forms a spatial image on the xy plane of the wafer 170. The spatial image is an intensity pattern formed by the light that reaches the wafer 170 after interacting with the mask 174. The spatial image is on the wafer 170 and extends approximately in the xy plane.

[0036] The system 100 can form a plurality of spatial images, each of which is spatially differently located along the z-axis of the wafer 170, during a single exposure pass. Further, referring to FIG. 1C showing a cross-sectional view of the yz plane of the wafer 170, the projection optical system 175 forms two spatial images 173a and 173b on different planes along the z-axis in a single exposure path. As will be discussed in more detail below, each of the spatial images 173a, 173b is formed from light having different primary wavelengths.

The position of the spatial image along the z-axis depends on the characteristics of the optical system 175 (with the projection lens 177 and the mask 174) and the wavelength of the light beam 160. The focal position of the lens 177 depends on the wavelength of the light incident on the lens 177. Therefore, the position of the spatial image can be controlled by changing or controlling the wavelength of the light beam 160. By supplying pulses with different primary wavelengths of light during a single exposure pass, multiple (two or more) spatial images, each at different positions along the z-axis, can be captured in optical system 175 (or optical system 175). (Any component of) and the wafer 170 can be formed in a single exposure pass without moving the wafer 170 with respect to each other along the z-axis.

[0038] In the example of FIG. 1A, the light that has passed through the mask 174 is focused on the focal plane by the projection lens 177. The focal plane of the projection lens 177 lies between the projection lens 177 and the wafer stage 171 and the position of the focal plane along the z-axis depends on the characteristics of the optical system 175 and the wavelength of the light beam 160. Since the spatial images 173a and 173b are formed from light having different wavelengths, they are located at different positions on the wafer 170. The spatial images 173a and 173b are separated from each other by a separation distance of 179 along the z-axis. The separation distance 179 depends on the difference between the wavelength of the light forming the spatial image 173a and the wavelength of the light forming the spatial image 173b.

[0039] The wafer stage 171 and mask 174 (or other component of the optical system 175) generally move relative to each other in the x, y, and z directions during scanning for normal performance correction and operation, eg, this. Motion can be used to achieve basic leveling, lens distortion correction, and stage positioning error correction. This relative motion is called ancillary motion. However, in the system of FIG. 1A, the relative motion of the wafer stage 171 and the optical system 175 is not utilized to form the separation distance 179. Instead, the separation distance 179 is formed by being able to control the primary wavelength of the pulse passing through the mask 174 during the exposure pass. Therefore, the separation distance 179, unlike some conventional systems, cannot be created simply by moving the optical system 175 and the wafer 170 relative to each other along the z-axis. Also, the spatial images 173a and 173b are both present on the wafer 170 during the same exposure pass. In other words, the system 100 does not require that the spatial image 173a be formed in the first exposure pass and the spatial image 173b is formed in the subsequent second exposure pass.

[0040] The light in the first spatial image 173a interacts with the wafer in the portion 178a, and the light in the second spatial image 173b interacts with the wafer in the portion 178b. These interactions can form electronic features or other physical features such as openings and holes on the wafer 170. Since the spatial images 173a, 173b are on different planes along the z-axis, the spatial images 173a, 173b can be used to form three-dimensional features on the wafer 170. For example, the spatial image 173a can be used to form a peripheral region, and the spatial image 173b can be used to form channels, trenches, or depressions at different positions along the z-axis. Therefore, the techniques discussed herein can be used to form 3D semiconductor components such as 3D NAND flash memory components.

[0041] Prior to discussing further details regarding the formation of multiple spatial images in a single exposure pass, exemplary implementations of the light source 105 and the photolithography system 100 are shown in FIGS. 2A-2C and 3A-3C. , And with reference to FIG.

[0042] With reference to FIG. 2A, a block diagram of the photolithography system 200 is shown. The system 200 is an exemplary implementation of the system 100 (FIG. 1A). For example, in the photolithography system 200, the light source 205 is used as the light source 105 (FIG. 1A). The light source 205 generates a pulsed light beam 260, and the pulsed light beam 260 is supplied to the lithography exposure apparatus 169. The light source 205 may be, for example, an excimer light source that outputs a pulsed light beam 260 (which may be a laser beam). When the pulsed light beam 260 enters the lithography exposure apparatus 169, the pulsed light beam 260 is guided through the projection optical system 175 and projected onto the wafer 170. In this way, one or more microelectron features are patterned on the photoresist on the wafer 170, the wafer 170 is then developed and washed prior to subsequent process steps, and the process is repeated. The photolithography system 200 also comprises a control system 250, which in the example of FIG. 2A is connected to a component of the light source 205 similar to the lithography exposure apparatus 169 to control various operations of the system 200. To. The control system 250 is an exemplary implementation of the control system 250 of FIG. 1A.

[0043] In the example shown in FIG. 2A, the light source 205 is a two-stage laser system including a main oscillator (MO) 212 that supplies a seed light beam 224 to the power amplifier (PA) 230. MO212 and PA230 may be considered as subsystems of light source 205, or systems that are part of light source 205. The power amplifier 230 receives the seed light beam 224 from the main oscillator 212 and amplifies the seed light beam 224 to generate a light beam 260 for use in the lithography exposure apparatus 169. For example, the main oscillator 212 can emit pulsed seed light beams with seed pulse energy of about 1 millijoule (mJ) per pulse, and these seed pulses are amplified to about 10-15 mJ by the power amplifier 230. be able to.

[0044] The main oscillator 212 includes a discharge chamber 240 having two elongated electrodes 217, a gain medium 219 which is a gas mixture, and a fan for circulating gas between the electrodes 217. A resonator is formed between the line narrowing module 216 on one side of the discharge chamber 240 and the output coupler 218 on the second side of the discharge chamber 240. The line narrowing module 216 can include diffractive optics such as a grid that finely adjusts the spectral output of the discharge chamber 240. 2B and 2C provide further details about the line narrowing module 216.

[0045] FIG. 2B is a block diagram of an exemplary implementation of the spectral feature selection module 258, including one or more examples of the line narrowing module 216. The spectral feature selection module 258 couples to the light propagating through the light source 205. In some implementations (eg, shown in FIG. 2B), the spectral feature selection module 258 receives light from chamber 214 of the main oscillator 212 and fine-tunes spectral features such as wavelength and bandwidth within the main oscillator 212. To enable.

[0046] The spectral feature selection module 258 can include control modules such as the spectral feature control module 254, which includes electronic components in the form of any combination of firmware and software. The control module 254 is connected to one or more operating systems, such as the spectral feature operating system 255_1 to 255_n. Each of the actuation systems 255_1 to 255_n may include one or more actuators connected to the respective optical features 256_1 to 256_n of the optical system 257. The optical features 256_1 to 256_n are configured to adjust the spectral features of the light beam 260 by adjusting the specific properties of the generated light beam 260. The control module 254 receives from the control system 250 a control signal containing specific commands for operating or controlling one or more of the operating systems 255_1 to 255_n. The operating systems 255_1 to 255_n can be selected and designed to work together, i.e. cooperate, or the operating systems 255_1 to 255_n can be configured to work individually. Also, the actuation systems 255_1 to 255_n can each be optimized to deal with a particular class of interference.

[0047] Each optical feature 256_1 to 256_n is optically coupled to a light beam 260 generated by the light source 105. The optical system 257 can be implemented as a line narrowing module 216C as shown in FIG. 2C. The line narrowing module includes a dispersion optical element such as a reflection grid 291 and a refraction optical element such as a prism 292, 293, 294, 295 as optical features 256_1 to 256_n. One or more of the prisms 292, 293, 294, 295 may be rotatable. An example of this line narrowing module can be found in US Application No. 12 / 605, 306 (Application '306) entitled SYSTEM METHOD AN APPARATUS FOR SELECTING AND CONTROLLING LIGHT SOURCE BANDWIDTH filed October 23, 2009. Can be done. Application No. 306 describes a line narrowing module with dispersion elements such as a beam expander (including one or more prisms 292, 293, 294, 295) and a grid 291. FIG. 2C does not show each actuating system of operable optical features such as one or more of grids 291 and prisms 292, 293, 294, 295.

[0048] Each of the actuators of the actuation system 255_1 to 255_n is a mechanical device for moving or controlling each optical feature 256_1 to 256_n of the optical system 257. The actuator receives energy from the module 254 and converts that energy into some sort of motion conferred on the optical features 256_1 to 256_n of the optical system 257. For example, application '306 describes an operating system such as a force device (for applying force to a region of a grid) and a rotating stage for rotating one or more of the prisms of a beam expander. There is. The operating system 255_1 to 255_n may include, for example, a motor such as a stepper motor, a valve, a pressure control device, a piezo device, a linear motor, a hydraulic actuator, and / or a voice coil.

[0049] In FIG. 2A seen above, the main oscillator 212 also modifies the line center analysis module 220 to receive the output light beam from the output coupler 218 and, if necessary, the size or shape of the output light beam. It comprises a beam coupled optical system 222 that forms a seed light beam 224. The line center analysis module 220 is a measurement system that can be used to measure or monitor the wavelength of the seed light beam 224. The line center analysis module 220 can be located at other locations within the light source 205 or at the output of the light source 205.

The mixed gas used in the discharge chamber 240 may be any gas suitable for producing a light beam at the wavelength and bandwidth required for this application. In the case of an excimer source, the mixed gas can include a noble gas (rare gas) such as argon or krypton other than the buffer gas helium and / or neon, such as fluorine or chlorine and a trace amount of halogen such as xenon. .. Specific examples of mixed gases are argon fluoride (ArF), which emits light at a wavelength of about 193 nm, krypton difluoride (KrF), which emits light at a wavelength of about 248 nm, or light emission at a wavelength of about 351 nm. Includes xenon chloride (XeCl). The excimer gain medium (mixed gas) is excited by a short (eg, nanosecond) current pulse during high-voltage discharge by applying a voltage to the elongated electrode 217.

The power amplifier 230 comprises a beam coupled optical system 232 that receives a seed light beam 224 from the main oscillator 212 and guides the light beam through the discharge chamber 240 to the beam turning optical element 248, wherein the beam coupled optical system 232 is seeded. The light beam 224 is redirected or altered to be sent back into the discharge chamber 240. The discharge chamber 240 includes a pair of elongated electrodes 241 and a gain medium 219 which is a mixed gas, and a fan for circulating the mixed gas between the electrodes 241.

[0052] The output light beam 260 is guided through a bandwidth analysis module 262 capable of measuring various parameters of the beam 260 (such as bandwidth and wavelength). The output light beam 260 can also be guided through the beam generation system 263. The beam generation system 263 may include, for example, a pulse stretcher in which each pulse of the output light beam 260 is stretched in time, for example in an optical delay unit, to adjust the performance characteristics of the light beam that collides with the lithography exposure apparatus 169. it can. The beam generation system 263 also includes other components that can act on the beam 260, such as reflective and / or refracting optics (eg lenses and mirrors), filters, and optical apertures (including automatic shutters). Can be prepared.

[0053] The photolithography system 200 also includes a control system 250. In the implementation shown in FIG. 2A, the control system 250 is connected to various components of the light source 205. For example, the control system 250 may control by transmitting one or more signals to the light source 205 when the light source 205 emits a pulse of light or a burst of light pulses containing one or more light pulses. it can. The control system 250 is also connected to the lithography exposure apparatus 169. Therefore, the control system 250 can also control various aspects of the lithography exposure apparatus 169. For example, the control system 250 can control the exposure of the wafer 170 and can therefore be used to control how the electronic features are printed on the wafer 170. In some implementations, the control system 250 can control the scanning of the wafer 170 by controlling the movement of the slit 176 in the xy plane (FIG. 1B). In addition, the control system 250 can exchange data with the metrology system 172 and / or the optical system 175.

[0054] The lithographic exposure apparatus 169 can also include, for example, a temperature control device (such as an air conditioning device and / or a heating device) and / or a power source for various electrical components. The control system 250 can also control these components. In some implementations, the control system 250 is implemented to include two or more sub-control systems, wherein at least one sub-control system (lithographic controller) controls aspects of the lithography exposure apparatus 169. It has become. In these implementations, the control system 250 can be used to control aspects of the lithography exposure apparatus 169 instead of or in addition to using the lithography controller.

[0055] The control system 250 includes an electronic processor 251, an electronic storage 252, and an I / O interface 253. The electronic processor 251 includes one or more processors suitable for executing a computer program, such as a general-purpose or dedicated microprocessor, and any one or more processors of any kind of digital computer. In general, electronic processors receive instructions and data from read-only memory, random access memory, or both. The electronic processor 251 may be any type of electronic processor.

[0056] The electronic storage 252 may be a volatile memory such as RAM or a non-volatile memory. In some implementations, the electronic storage 252 comprises non-volatile and volatile parts or components. The electronic storage 252 can store data and information used in the operation of the control system 250, the components of the control system 250, and / or the system controlled by the control system 250. The information can be stored, for example, in a look-up table or database. For example, the electronic storage 252 can store data indicating values of various characteristics of the beam 260 under different operating conditions and performance scenarios.

[0057] The electronic storage 252 can also store various recipes or processing programs 259 that determine the parameters of the light beam 260 during use. For example, the electronic storage 252 can store a recipe indicating the wavelength of each pulse in the light beam 260 for a particular exposure path. The recipe can show different wavelengths for different exposure passes. The wavelength control techniques discussed below can be applied on a pulse-by-pulse basis. In other words, the wavelength component can be controlled for each individual pulse in the exposure path to facilitate the formation of a spatial image at a desired position along the z-axis.

The electronic storage 252 can also store instructions, perhaps computer programs, that, when executed, cause the processor 251 to communicate with the control system 250, the optical system 205, and / or the components in the lithography exposure apparatus 169.

[0059] The I / O interface 253 allows the control system 250 to include an operator, an optical system 205, a lithography exposure device 169, an optical system 205 and / or any component or system within the lithography exposure device 169, and / or another electronic device. An electronic interface of any kind that allows data and signals to be received and / or provided to and from an automated process operating in. For example, the I / O interface 253 can include one or more of an image display device, a keyboard, and a communication interface.

[0060] The light beam 260 (and the light beam 160) is a pulsed light beam and can include bursts of one or more pulses separated from each other in time. Each burst can contain one or more pulses of light. In some implementations, the burst contains hundreds of pulses, eg 100-400 pulses. 3A-3C provide an overview of pulse and burst generation at light source 205. FIG. 3A shows the amplitude of the wafer exposure signal 300 as a function of time, FIG. 3B shows the amplitude of the gate signal 315 as a function of time, and FIG. 3C shows the amplitude of the trigger signal as a function of time.

[0061] The control system 250 can be configured to transmit a wafer exposure signal 300 to the light source 205 in order to control the light source 205 to generate the light beam 260. In the example shown in FIG. 3A, the wafer exposure signal 300 has a high value of 305 (eg, 1) for period 307, which is the period during which light source 205 produces bursts of optical pulses. In another situation, the wafer exposure signal 300 has a low value of 310 (eg 0) when the wafer 170 is not exposed.

[0062] With reference to FIG. 3B, the light beam 260 is a pulsed light beam and the light beam 260 includes a pulse burst. The control system 250 also controls the duration and frequency of the pulse burst by transmitting a gate signal 315 to the light source 205. The gate signal 315 has a high value of 320 (eg, 1) during pulse bursts and a low value of 325 (eg, 0) during the time between continuous bursts. In the example shown, the period during which the gate signal 315 has a high value is also the duration of burst 316. Bursts are separated in time by the time interval between bursts. During the time interval between bursts, the lithography exposure apparatus 169 can place the next die on the wafer 170 for exposure.

[0063] With reference to FIG. 3C, the control system 250 also uses the trigger signal 330 to control the repetition rate of the pulses within each burst. The trigger signal 330 includes a trigger 340, one of which is supplied to the light source 205 to cause the light source 205 to generate an optical pulse. The control system 250 can send a trigger 340 to the light source 205 each time a pulse is to be generated. Therefore, the repetition rate (time between two continuous pulses) of the pulse generated by the light source 205 can be set by the trigger signal 330.

[0064] As described above, the gain medium 219 emits light when the gain medium 219 is excited by applying a voltage to the electrodes 217. When the voltage is applied to the electrode 217 in pulses, the light emitted from the medium 219 is also pulsed. Therefore, the repetition rate of the pulsed light beam 260 is determined by the rate at which the voltage is applied to the electrode 217, and each time a voltage is applied, a light pulse is generated. The optical pulse propagates through the gain medium 219 and exits the chamber 214 through the output coupler 218. Therefore, a pulse train is generated by periodically and repeatedly applying a voltage to the electrode 217. The trigger signal 330 can be used, for example, to control the application of voltage to the electrode 217 and the pulse repeat rate, with the pulse repeat rate between about 500 and 6,000 Hz in most applications. There is a possibility. In some implementations, the repeat rate may be greater than 6,000 Hz, for example 12,000 Hz or higher.

The signal from the control system 250 also controls the pulse energy of the main oscillator 212 and the power amplifier 230, and thus the energy of the light beam 260, so that the electrodes 217, 241 in the main oscillator 212 and the power amplifier 230 are also controlled. Can be used to control each. There may be a delay between the signal fed to the electrode 217 and the signal fed to the electrode 241. The amount of delay can affect the characteristics of the beam 260, such as the amount of coherence in the pulsed light beam 260.

The pulsed light beam 260 can have an average output power in the range of tens of watts, eg, about 50W to about 130W. Irradiance of the light beam 260 at the output (i.e., the average power per unit area) ^is likely to extend to ^{60W / cm 2 ~80W / cm 2} .

Further, referring to FIG. 4, the wafer 170 is irradiated with the light beam 260. The lithography exposure apparatus 169 includes an optical system 175 (FIGS. 1A and 1B). In the example of FIG. 4, the optical system 175 (not shown) includes an illuminator system 429 with an objective configuration 432. The objective configuration 432 includes a projection lens 177 (FIG. 1B) and enables image transfer from the mask 174 to the photoresist on the wafer 170. The illuminator system 429 adjusts the angular range of the light beam 260 that hits the mask 174. The illuminator system 429 can also equalize (uniformize) the intensity distribution of the light beam 260 in the xy plane across the mask 174.

[0068] In some implementations, an immersion medium may be supplied to cover the wafer 170. The immersion medium may be a liquid for immersion lithography (such as water). In other embodiments where the lithography is dry, the immersion medium may be a gas such as dry nitrogen, dry air, or clean air. In other implementations, the wafer 170 can be exposed inside a pressure controlled environment (such as vacuum or partial vacuum).

[0069] During the exposure pass, the plurality of N pulses of the light beam 260 illuminate the same area of the wafer 170. N is any integer greater than 1. The pulse number N of the light beam 110 that illuminates the same area is sometimes referred to as the exposure window or exposure path 400. The size of the window 400 can be controlled by the slit 176. For example, the slit 176 can include a plurality of blades, which are movable to form an aperture in one shape and close the aperture in the other shape. The size of the window 400 can also be controlled by arranging the blades of the slit 176 so as to form an aperture of a particular size.

[0070] N pulses also determine the amount of illumination in the exposure path. The amount of illumination is the amount of light energy delivered to the wafer during the exposure pass. Therefore, the characteristics of N pulses, such as the light energy of each pulse, determine the amount of illumination. Also, as discussed in more detail below, the N pulses can also be used to determine the amount of light in each spatial image 173a, 173b. Specifically, in the recipe, of the N pulses, a certain number of pulses have a first primary wavelength that forms the spatial image 173a, and a certain number of pulses form the spatial image 173b. It can be specified that it has a primary wavelength.

Further, the slit 176 and / or the mask 174 moves in the scan direction in the xy plane so that only a part of the wafer 170 is exposed at a predetermined time or during a specific exposure scan (or exposure pass). can do. The size of the area exposed by the light beam 160 on the wafer 170 is determined by the distance between the blades in the non-scan direction and by the length (distance) of the scan in the scan direction. In some implementations, the value of N is tens, for example 10 to 100 pulses. In other embodiments, the value of N is greater than 100 pulses, for example 100-500 pulses. The exposure field 479 of the wafer 170 is the physical area of the wafer 170 that is exposed in a single scan of the exposure slit or window within the lithography exposure apparatus 169.

[0072] Wafer stages 171 and masks 174, and objective configuration 432 are attached to the associated operating system to form a scan configuration. In the scan configuration, one or more of the mask 174, the objective configuration 432, and the wafer 170 (via stage 171) can move relative to each other in the xy plane. However, apart from the incidental relative motion between the wafer stage 171 and the mask 174, and the objective configuration 432, these elements do not move relative to each other along the z-axis during the exposure or exposure pass.

[0073] With reference to FIG. 5, a flowchart of process 500 is shown. Process 500 is an example of a process for forming a three-dimensional semiconductor component or a portion of such a component. Process 500 can be performed using the photolithography system 100 or 200. Process 500 is considered for the system 200 shown in FIG. 2A. Process 500 is also considered with respect to FIGS. 6A-10B.

[0074] Direct the light beam 260 toward the mask 174 (510). The light beam 260 is a pulsed light beam each containing a plurality of pulses separated from each other in time as shown in FIG. 3C. 6A and 6B show examples of single pulse optical spectra that are part of the light beam 260. Other pulses of light beam 260 can have different optical spectra.

[0075] With reference to FIG. 6A, the optical spectrum 601A of the optical pulse 600A is shown. The pulse 600A has a non-zero intensity in the wavelength band. The wavelength band is sometimes referred to as the bandwidth of the pulse 600A.

[0076] The information shown in FIG. 6A is the instantaneous optical spectrum 601A (or emission spectrum) of the pulse 600A. The optical spectrum 601A contains information about how the light energies or powers of the pulses of the light beam 260 are distributed at different wavelengths (or frequencies). The optical spectrum 601A is drawn graphically and the spectral intensity (not necessarily with absolute calibration) is plotted as a function of wavelength or optical frequency. The optical spectrum 601A is sometimes referred to as the spectral shape or intensity spectrum of the pulse of the light beam 260. The pulse 600A has a primary wavelength of 602A, which is the peak intensity in the example of FIG. 6A. Though the discussion of the spatial image formed by the pulse of light beam 260 and the pulse of light beam 260 refers to the primary wavelength of the pulse, the pulse contains wavelengths other than the primary wavelength and has a finite bandwidth that can be characterized by metrics. Has. For example, the overall width (referred to as FWXM) of spectrum 601A, which is a fraction (X) of the maximum peak intensity of the spectral shape, can be used to characterize the light beam bandwidth. As another example, the width of the spectrum (referred to as EY), including the fraction of the integrated spectral intensity (Y), can be used to characterize the light beam bandwidth.

[0077] Pulse 600A is shown as an example of a pulse that may be present in the light beam 260. When a portion of the wafer 120 is exposed using the pulse 600A, the light of the pulse forms a spatial image. The position of the spatial image in the z direction (FIGS. 1C and 4) is determined by the value of the primary wavelength 602A. The various pulses of the light beam 260 can have different primary wavelengths. For example, in order to generate two spatial images during a single exposure pass, some pulses of the light beam 260 have one primary wavelength (first primary wavelength) and the other pulse of the light beam 260. Has another primary wavelength (second primary wavelength). The first and second primary wavelengths are different wavelengths. The wavelength difference between the first and second primary wavelengths is sometimes referred to as spectral separation. The spectral separation may be, for example, 200 femtometres (fm) to 5 picometers (pm). The wavelengths of the various pulses of the light beam 260 may be different, but the shape of the optical spectrum of the pulses may be the same.

[0078] The light source 205 dithers the primary wavelength for each pulse so that every pulse has a different primary wavelength than the pulse immediately before or after the pulse in time, that is, between the first and second primary wavelengths. You can switch with. In these implementations, assuming that all pulses of the light beam 260 have the same intensity, the distribution of the first and second primary wavelengths in this way has the same intensity at different positions in the z direction. It gives rise to two spatial images.

[0079] In some embodiments, a portion (eg, 33%) of the pulse has a first primary wavelength and the remaining portion (67% in this example) has a second primary wavelength. In these implementations, two spatial images with different intensities are formed, assuming that all pulses of the light beam 260 have the same intensity. The spatial image formed by the pulse having the first primary wavelength has about half the intensity of the spatial image formed by the pulse having the second primary wavelength. In this way, the dose delivered to a particular location along the z-axis of the wafer 170 can be controlled by controlling a portion of N pulses having each of the first and second primary wavelengths. it can.

[0080] A portion of the pulse that will have a particular primary wavelength for the exposure path can be specified in the recipe file 259 stored in the electronic storage 252. Recipe 259 defines the proportion of various primary wavelengths for the exposure pass. Recipe 259 can also specify proportions for other exposure passes so that different proportions can be used for other exposure passes and the spatial image can be adjusted or controlled on a field-by-field basis. ..

[0081] With reference to FIG. 6B, the optical spectrum 601B of pulse 600B is shown. Pulse 600B is another example of a pulse of light beam 260. The optical spectrum 601B of the pulse 600B has a different shape from the optical spectrum 601A. Specifically, the optical spectrum 601B has two peaks corresponding to the two primary wavelengths 602B_1 and 602B_2 of the pulse 600B. The pulse 600B is part of the light beam 260. When a portion of the wafer 120 is exposed using the pulse 600B, the light of the pulse forms two spatial images at different positions along the z-axis on the wafer. The position of the spatial image is determined by the wavelengths of the primary wavelengths 602B_1 and 602B_2.

[0082] The pulses shown in FIGS. 6A and 6B can be formed by any hardware capable of forming such pulses. For example, a pulse train of pulses such as pulse 600A can be formed using a line narrowing module similar to the line narrowing module 216C of FIG. 2C. The wavelength of the light diffracted by the grid 291 depends on the angle of the light incident on the grid. A mechanism that changes the angle of incidence of light interacting with the lattice 291 can be used with such a line narrowing module to create a pulse train containing N pulses for an exposure path, N. At least one of the pulses has a primary wavelength different from the primary wavelength of another of the N pulses. For example, one of the prisms 292, 293, 294, and 295 can be rotated to change the angle of light incident on the grid 291 for each pulse. In some implementations, the line narrowing module is in the path of the beam 260 and includes a movable mirror to change the angle of light incident on the grid 291. Examples of such implementations are discussed, for example, in US Pat. No. 6,192,064, entitled NARROW BAND LASER WITH FINE WAVELENGTH CONTROL, published February 20, 2001.

[0083] Pulses such as pulse 600B (FIG. 6B) can also be formed using a line narrowing module similar to the line narrowing module 216C of FIG. 2C. For example, stimulated optics such as an acoustic optics modulator can be placed in the line narrowing module 216C on the path of the beam 260. The acoustic-optical modulator deflects the incident light at an angle that depends on the frequency of the sound waves used to excite the modulator. The acoustic modulator comprises a material such as glass or quartz that allows the propagation of sound waves, and a transducer combined with the material. The transducer vibrates in response to an excitation signal, which produces sound waves in the material. The sound waves form a moving expansion surface and a moving compression surface that change the refractive index of the material. As a result, the sound waves act as a diffraction grating that diffracts the incident light and exit the material at several different angles at the same time. Light from two or more orders can reach the grid 291 and each light of various diffraction orders has a different angle of incidence with respect to the grid 291. In this way, a single pulse containing two or more primary wavelengths can be formed. An example of a line narrowing module with an acoustic-optical modulator is considered, for example, in US Pat. No. 7,154,928, entitled LASER OUTPUT BEAM WAVEFRONT SPLITTER FOR BANDWIDTH SPECTRUM CONTROL, issued December 26, 2006.

[0084] During a single exposure pass, a set of optical pulses is directed at wafer 170 and passed through mask 174 (520). As discussed above, N light pulses can be supplied to the wafer 170 during the exposure pass. The N light pulses may be continuous light pulses of the beam 260. The exposed portion of the wafer 170 is the average of the optical spectra of each of the N pulses during the exposure pass. Therefore, if a portion of the N pulses has a first primary wavelength and the rest of the N pulses have a second primary wavelength, the average optical spectrum on the wafer 170 will be the peak at the first primary wavelength. The optical spectrum includes the peak at the second primary wavelength. Similarly, if all or part of the individual pulses of the N pulses have more than one primary wavelength, those primary wavelengths can peak in the average optical spectrum. FIG. 7 shows an example of the average optical spectrum 701 on the wafer 170. The average optical spectrum 701 includes a first primary wavelength 702_1 and a second primary wavelength 702_2. In the example of FIG. 7, the first primary wavelength 702_1 and the second primary wavelength 702_2 are separated by a spectral separation 703 of about 500 fm, but other combinations are possible. The spectral separation 703 includes a spectral region 704 in which the first primary wavelength 702_1 and the second primary wavelength 702_2 are different and the average optical spectrum 701 has little or no intensity between the wavelengths 702_1 and 702_2.

[0085] Two or more spatial images, such as a first spatial image based on the first primary wavelength and a second spatial image based on the second primary wavelength, are transferred to the wafer 170 based on the average optical spectrum. It is formed (530). Continuing with the example of the average optical spectrum 701 and further referring to FIG. 8A, two spatial images 873a and 873b are formed in a single exposure pass based on N pulses. The N pulses include a pulse having a first primary wavelength 702_1 and a pulse having a second primary wavelength 702_2. The pulse having the first primary wavelength 702_1 forms the first spatial image 873a, and the pulse having the second primary wavelength 702_2 forms the second spatial image 873b. The spatial image 873a is formed on the first plane 878a, and the spatial image 873b is formed on the second plane 878b. The planes 878a and 878b are perpendicular to the propagation direction of the light beam 260 on the wafer 170. The planes 878a and 878b are separated by a separation distance of 879 along the z direction.

[0086] The separation distance 879 is larger than the depth of focus of the lithographic apparatus 169 for the average optical spectrum having a single primary wavelength. Depth of focus is in the z direction, which provides a feature size that is within the feature size tolerance for the process in which the dose is applied to the wafer 170 with respect to the dose value (the amount of light energy delivered to the wafer). It can be defined as the focal range along. Process 500 can increase the depth of focus of the lithography exposure apparatus 169 by providing the wafer 170 with two or more different spatial images during a single exposure pass. This is because the plurality of spatial images can each expose wafers at different positions in the z direction using features that are within the allowable range of the feature size. In other words, the process 500 can provide a wider depth of focus with the lithographic exposure apparatus 169 during a single exposure pass. As discussed above, the operator of the lithography exposure apparatus 169 can use the recipe file 259 to control various parameters of the exposure process. In some implementations, the operator of the lithography exposure apparatus 169 can obtain information from a simulation program such as Tachyon Source-Mask Optimization (SMO) commercially available from Brion, a subsidiary of ASML. Can be used to program or specify parameters for recipe file 259. For example, the operator of the lithography exposure apparatus 169 may know that the next lot will not require as much depth of focus as the previously exposed lot. In this example, the operator specifies the depth of focus and dose variation in the simulation program, which returns the values of spectral separation 703 to obtain the desired parameters. The operator can then specify the value of spectrum separation 703 for the next lot by programming the recipe file 259 using the I / O interface 253. In some implementations, does the operator use simulation to require a greater depth of focus for a particular exposure path (eg, possible by exposing wafer 170 with multiple spatial images in different planes)? You can decide whether or not. If a greater depth of focus is not required to form a particular portion of the semiconductor component, the recipe file 259 will, for example, have a single primary wavelength exposure path used to form that particular portion of the semiconductor component. It can be configured to have an average optical spectrum that includes.

[0087] Operators and / or simulators can also obtain information about the formed 3D components as measured by the metrology system 172 or by another sensor. For example, the metrology system 172 can provide data on the sidewall angles of the formed 3D semiconductor components and use this data to program the parameters in the recipe file 259 for subsequent exposure passes. Can be done.

[0088] FIG. 8B shows a spatial image 873a of the xy plane (looking into the paper surface of FIG. 8A) on the plane 878a. Spatial images 873a and 873b are generally two-dimensional intensity patterns formed on the xy plane. The nature of this intensity pattern depends on the properties of the mask 174. The first and second planes 878a and 878b are a part of the wafer 170. As shown in FIG. 8B, the first plane 878a may be only a small portion of the entire wafer 170.

The value of the separation distance 879 depends on the characteristics of the spectral separation 703 and the optical system 275. For example, the value of the separation distance 879 may depend on the focal length, aberrations, and other properties of the lens and other optical elements in the optical system 275. For a scanner lens with chromatic aberration C, the separation distance 879 can be determined from Equation 1.
ΔD = C * Δλ equation (1)
In the equation, ΔD is the separation distance 879 (unit: nanometer (nm)), C is the chromatic aberration (defined as the distance the focal plane moves in the propagation direction due to wavelength change), and Δλ is the spectral separation. It is 873 (unit: picometer). The separation distance 875 may be, for example, 5000 nm (5 μm) and the spectral separation 873 may be about 200-300 fm.

[0090] Also, due to changes in the manufacturing and installation process and / or changes by the end user, different primary wavelengths are required to achieve the desired separation distance 879 for certain examples of certain types of lithography exposure equipment 169. There is a possibility of becoming. As discussed above, the recipe or process control program 259 can be stored in the electronic storage 252 of the control system 250. Recipe 259 can be modified or programmed to be customized for a particular exposure device or certain type of exposure device. Recipe 259 can be programmed when the lithography system 200 is manufactured, and / or Recipe 259 is an end user or other operator familiar with the operation of the system 200, eg, via the I / O interface 253. Can be programmed by.

Recipe 259 can also specify different separation distances 879 for different exposure passes used to expose different areas of wafer 170. Additional or alternative, Recipe 259 can specify a separation distance of 879 for each lot, layer, or wafer. A lot or layer is a group of wafers processed by the same exposure equipment under the same nominal conditions. Recipe 259 also makes it possible to specify other parameters related to spatial images 873a, 873b, such as the dose provided by each image. For example, Recipe 259 can specify the ratio of the number of pulses having the first primary wavelength 702_1 to the number of pulses having the second primary wavelength 702_2 out of N pulses. These other parameters can also be specified per field, per lot (or per layer), and / or per wafer.

[0092] Also, in Recipe 259, some layers are not exposed at the first primary wavelength 702_1 and the second primary wavelength 702_2, but instead are exposed with a pulse having an optical spectrum containing a single primary wavelength. Can be stipulated. Such an optical spectrum can be used, for example, when trying to form a planar semiconductor component instead of a three-dimensional semiconductor component. The I / O interface 253 allows the end user and / or manufacturer to program a recipe that defines the number of primary wavelengths, including scenarios where a single primary wavelength is used, eg, for a particular layer or lot. Allows you to create.

[0093] Further, the above example considers an average optical spectrum 701 having two primary wavelengths, but in another example, the average optical spectrum 701 has three or more primary wavelengths (for example, three or four). It can have one or five primary wavelengths), each of which is separated from the nearest other primary wavelength in a region such as spectral separation and region 704. The I / O interface 253 allows end users and / or manufacturers to program or create recipes that specify these parameters.

[0094] Three-dimensional (3D) semiconductor components are formed (540). FIG. 9A shows a cross-sectional view of an exemplary 3D semiconductor component 995. FIG. 9B shows the wafer 170 and the xy plane component 995 on the first plane 878a. The 3D semiconductor component 995 may be a complete component or part of a larger component. The 3D semiconductor component 995 may be any type of semiconductor component that has features that are not all formed in one z position within the wafer 170. For example, a 3D semiconductor component may be a device with a recess or opening that extends along the z-axis. For example, the 3D semiconductor component may be all or part of the 3D NAND flash memory component. The 3D NAND flash memory is a memory in which memory cells are stacked along the z-axis.

[0095] In the example of FIG. 9A, the 3D semiconductor component 995 includes a recess 996 formed on the outer surface 999. The recess 996 includes a floor 997 and a side wall 998 extending approximately along the z-axis between the outer surface 999 and the floor 997. The floor 997 is formed by exposing the photoresist on the plane 878b with the light in the second spatial image 873b (FIG. 8A). The features on the outer surface 999 are formed using the light in the first spatial image 873a (FIG. 8A).

Using process 500 can also result in a side wall angle 992 equal to 90 ° or closer to 90 ° than is possible with other processes. The side wall angle 992 is the angle between the floor 997 and the side wall 998. If the side wall 998 extends in the xz plane and the floor extends in the xy plane, the side wall angle 992 is 90 ° and can be considered vertical in this example. Vertical side wall angles are desirable. This is because, for example, such sidewalls allow for better defined features of 3D semiconductor components. Process 500 achieves a side wall angle of 992 equal to or close to 90 °. This is because the positions of the first spatial image 873a and the second spatial image 873b (the first plane 878a and the second plane 878b, respectively) are distant images in different parts of the wafer 170. Forming distant spatial images in a single exposure pass can improve the quality of each image and is more vertically oriented than features formed by a single low quality spatial image. Brings clear features.

[0097] FIGS. 10A and 10B are examples of simulated data related to process 500. FIG. 10A shows three plots 1001, 1002, 1003 of the spatial image intensity vs. the mask position along the y-axis (FIG. 9A). Each plot 1001, 1002, 1003 represents the intensity vs. mask position of one spatial image. In FIG. 10A, plot 1001 represents a simulation of an average optical spectrum that forms two spatial images during a single exposure pass as described above for FIG. Plot 1002 represents a simulation of a situation where the wafer stage is tilted according to ASML's EFESE technique, which is a procedure for increasing the depth of focus to facilitate printing of 3D features (vias, holes, etc.) on a wafer. In EFESE technology, the wafer stage is tilted at an angle to expose the wafer and scan the spatial image through the focal point. EFESE technology generally provides greater depth of focus. In FIG. 10A, only plot 1002 represents data simulated using EFESE technology. The remaining data shown in FIG. 10A did not employ EFESE technology. Plot 1003 represents data from a dose-based best focus simulation.

The spatial image intensity as a function of the mask position shown in FIG. 10A may produce contrast similar to tilting the wafer stage to form two or more spatial images in a single exposure pass. Show that. Higher contrast indicates that 3D features (FIG. 8A) at different positions along the z-axis are more likely to be properly formed.

[0099] FIG. 10B shows three plots 1004, 1005, 1006 of critical dimensions as a function of focal position for three different spatial images, each averaged during the exposure pass. Plot 1004 in FIG. 10B represents data from a simulation that formed a single spatial image without applying EFESE technology. Plot 1005 represents data from a simulation to which EFESE technology is applied. As shown in the figure, the EFESE technique increases the depth of focus compared to simulations without the application of EFESE, because the critical dimension value does not change further away from the zero focus. Plot 1005 represents data from a simulation in which two spatial images were generated in a single exposure pass and no EFESE technique was applied. The depth of focus of simulations with multiple spatial images and without EFESE technology is comparable or better than EFESE technology. Therefore, a larger depth of focus can be achieved in a single exposure pass using process 500 without resorting to techniques such as EFESE.

[0100] Embodiments can be further described with the following provisions.
1. 1. A method of forming a three-dimensional semiconductor component using a photolithography system.
Directing a pulsed light beam containing multiple light pulses toward the mask along the propagation direction,
Directing a set of light pulses of light beam through a mask to a wafer during a single exposure pass,
To generate at least a first spatial image and a second spatial image on a wafer based on the optical pulses in a pulse set passing through the mask during a single exposure pass, the first spatial image. Is on the first plane on the wafer, the second spatial image is on the second plane on the wafer, and the first and second planes are separated from each other by a separation distance along the propagation direction. , And the interaction of the light of the first spatial image with the material of the first part of the wafer and the interaction of the light of the second spatial image with the material of the second part of the wafer to the photoresist. Including patterning 3D semiconductor components,
By having at least one of the pulses in the pulse set having a first primary wavelength and at least one of the other pulses in the pulse set having a second primary wavelength different from the first primary wavelength, the first and second A method in which the spectra of the second pulse set are spectrally different and the separation distance is based on the difference between the first and second primary wavelengths.
2. 2. The method of clause 1, wherein at least one of the pulses in a pulse set passing through the mask during a single exposure pass comprises two or more primary wavelengths of light.
3. 3. The method of Clause 2, wherein each primary wavelength is separated by a spectral separation of 200 femtometres (fm) to 500 picometers (pm) from the nearest alternative primary wavelength.
4. The method of clause 1, wherein the separation distance between the first spatial image and the second spatial image varies during a single exposure pass.
5. The single exposure pass is the first exposure pass, and the method further passes through the mask during the second exposure pass and after the first exposure pass is completed, through a second set of light pulses of light beam. The method of clause 1, wherein the separation distance between the first spatial image and the second spatial image differs between the first and second exposure passes, including directing the light to the wafer.
6. The method of clause 1, wherein the separation distance between the first spatial image and the second spatial image is set prior to the single exposure pass and the separation distance does not change during the single exposure pass.
7. The method of clause 6, wherein the separation distance between the first spatial image and the second spatial image is set to adapt to one or more features of the photolithography system.
8. The pulse set includes a first group of optical pulses and a second group of optical pulses, each pulse of the first group of optical pulses having a first primary wavelength and a second group of optical pulses. Each pulse of has a second primary wavelength, and the method further
Controlling the light intensity of the first spatial image by controlling the characteristics of the first group of pulses, and controlling the light intensity of the second spatial image by controlling the characteristics of the second group of pulses. The method described in Clause 1, including.
9. The method of clause 8, wherein the characteristics of the first group include the number of pulses of the first group and the characteristics of the second group include the number of pulses of the second group.
10. Controlling the number of pulses in the first group involves determining the number of first pulses included in the first group of pulses before the start of a single exposure pass, including the pulses in the second group of pulses. The method of clause 9, wherein controlling the number determines the number of second pulses included in the second group of pulses prior to a single exposure pass.
11. Determining the number of first and second pulses is (a) receiving input from the operator and (b) accessing pre-defined settings associated with the photolithography system. The method according to clause 10, including one or more.
12. The method of Clause 8, wherein the characteristics of the first group of pulses include the intensity of each pulse of the first group and the characteristics of the second group of pulses include the intensity of each pulse of the second group.
13. The method of clause 1, wherein the first plane on the wafer and the second plane on the wafer are planes that are substantially perpendicular to the propagation direction.
14. 9. The method of clause 9, wherein the first group of pulses and the second group of pulses include all pulses that pass through the mask in a single exposure pass.
15. The first feature of the 3D semiconductor is formed in the first plane,
A second feature of the 3D semiconductor is formed in the second plane,
The method of clause 1, wherein the first and second features are separated from each other by side walls that extend substantially parallel to the propagation direction.
16. The method of clause 1, wherein the 3D semiconductor component comprises a 3D NAND flash memory component.
17. The first plane corresponds to the first focal plane, the second plane corresponds to the second focal plane, and the separation distance between the first plane and the second plane corresponds to the optical pulse passing through the mask. The method of clause 1, based on the difference in wavelengths of one or more of the pulses, or the difference in wavelength between individual pulses of a pulse set.
18. Light source and
A mask arranged to interact with the pulsed light beam from the light source,
A lithographic scanner device with a wafer holder and
A photolithography system with a control system coupled to a light source.
The control system is configured to cause the light source to emit a pulsed light beam toward the lithography scanner device during a single exposure pass, at least a first spatial image and a second spatial image during the single exposure pass. Is formed on a wafer supported by a wafer holder based on a set of light pulses of light pulses passing through the mask along the propagation direction, with a first spatial image in the first plane on the wafer. , The second spatial image is in the second plane on the wafer, the first plane and the second plane are separated from each other by a separation distance along the propagation direction, and the three-dimensional semiconductor component is the first. It is formed based on the interaction between the light of the spatial image and the material of the first part of the wafer and the light of the second spatial image and the material of the second part of the wafer.
At least one of the pulses in the pulse set has a first primary wavelength and
At least one of the other pulses in the pulse set has a second primary wavelength that is different from the first primary wavelength so that the spectra of the first and second sets of pulses are spectrally different.
A photolithography system in which the separation distance is based on the difference between the first primary wavelength and the second primary wavelength.
19. The control system comprises a computer-readable storage medium, one or more electronic processors combined with the computer-readable storage medium, an input / output interface, and recipes related to the photolithographic system are stored in the computer-readable storage medium. , The photolithographic system according to Clause 18.
20. The photolithography system according to Clause 19, wherein the recipe specifies the separation distance.
21. The photolithography system according to Clause 20, wherein the recipe specifies a separation distance for each wafer or lot.
22. The photolithography system according to Clause 18, wherein the light source comprises a krypton fluoride (KrF) gain medium or an argon fluoride (ArF) gain medium.

[0101] Other implementations are within the scope of the claims.

Claims (22)

A method of forming 3D semiconductor components using a photolithography system.
Directing a pulsed light beam containing multiple light pulses toward the mask along the propagation direction,
A set of said light pulses of said light beam passed through the mask and directed at the wafer during a single exposure pass.
To generate at least a first spatial image and a second spatial image on the wafer based on the optical pulses in the pulse set passing through the mask during the single exposure pass. The first spatial image is on the first plane on the wafer, the second spatial image is on the second plane on the wafer, and the first plane and the second plane are in the propagation direction. Being separated from each other by the separation distance along
A photo based on the interaction between the light of the first spatial image and the material of the first portion of the wafer and the interaction of the light of the second spatial image with the material of the second portion of the wafer. The resist includes patterning the three-dimensional semiconductor component.
By having at least one of the pulses in the pulse set having a first primary wavelength and at least one of the other pulses in the pulse set having a second primary wavelength different from the first primary wavelength. The spectra of the first and second pulse sets are spectrally different,
A method in which the separation distance is based on the difference between the first primary wavelength and the second primary wavelength. The method of claim 1, wherein at least one of the pulses in the pulse set passing through the mask during the single exposure pass comprises two or more primary wavelengths of light. The method of claim 2, wherein each primary wavelength is separated by a spectral separation of 200 femtometres (fm) to 500 picometers (pm) from another closest primary wavelength. The method of claim 1, wherein the separation distance between the first spatial image and the second spatial image varies during the single exposure pass. The single exposure pass is the first exposure pass.
The method further comprises directing a second set of light pulses of the light beam through the mask to the wafer during the second exposure pass and after the first exposure pass is completed. ,
The method of claim 1, wherein the separation distance between the first spatial image and the second spatial image differs between the first exposure pass and the second exposure pass. The separation distance between the first spatial image and the second spatial image is set prior to the single exposure pass.
The method of claim 1, wherein the separation distance does not change during the single exposure pass. The method of claim 6, wherein the separation distance between the first spatial image and the second spatial image is set to adapt to one or more features of the photolithography system. The pulse set includes a first group of optical pulses and a second group of optical pulses.
Each pulse in the first group of light pulses has the first primary wavelength.
Each pulse in the second group of light pulses has the second primary wavelength.
The above method further
Controlling the amount of light in the first spatial image by controlling the characteristics of the first group of pulses,
Controlling the amount of light in the second spatial image by controlling the characteristics of the second group of pulses,
The method according to claim 1, wherein the method comprises. The characteristics of the first group include the number of pulses of the first group.
The method of claim 8, wherein the characteristics of the second group include the number of pulses of the second group. Controlling the number of pulses in the first group includes determining the number of first pulses included in the first group of pulses before the single exposure pass begins.
9. Controlling the number of pulses in a second group of pulses comprises determining the number of second pulses included in the second group of pulses prior to the single exposure pass. The method described in. Determining the number of first and second pulses (a) receives input from the operator and (b) accesses pre-defined settings associated with the photolithography system. The method of claim 10, comprising one or more of the above. The characteristics of the first group of the pulses include the intensity of each pulse of the first group.
8. The method of claim 8, wherein the properties of the second group of pulses include the intensity of each pulse of the second group. The method according to claim 1, wherein the first plane on the wafer and the second plane on the wafer are planes substantially perpendicular to the propagation direction. 9. The method of claim 9, wherein a first group of the pulses and a second group of the pulses include all pulses that pass through the mask in the single exposure pass. The first feature of the three-dimensional semiconductor is formed on the first plane.
A second feature of the three-dimensional semiconductor is formed on the second plane.
The method of claim 1, wherein the first and second features are separated from each other by a side wall extending substantially parallel to the propagation direction. The method of claim 1, wherein the three-dimensional semiconductor component comprises a three-dimensional NAND flash memory component. The first plane corresponds to the first focal plane,
The second plane corresponds to the second focal plane,
The separation distance between the first plane and the second plane is based on the difference in wavelength of one or more of the light pulses passing through the mask, or the difference in wavelength between the individual pulses of the pulse set. , The method according to claim 1. Light source and
A lithography scanner apparatus having a mask and a wafer holder arranged to interact with a pulsed light beam from the light source.
A control system coupled to the light source
It is a photolithography system equipped with
The control system is configured to cause the light source to emit the pulsed light beam towards the lithography scanner device during a single exposure pass, at least a first spatial image and during the single exposure pass. A second spatial image is formed on the wafer supported by the wafer holder based on a set of optical pulses of optical pulses that pass through the mask along the propagation direction, and the first spatial image is said. It is on the first plane on the wafer, the second spatial image is on the second plane on the wafer, and the first plane and the second plane are separated by the separation distance along the propagation direction. Separated from each other, the three-dimensional semiconductor components interact with the light of the first spatial image and the material of the first portion of the wafer and the light of the second spatial image and the second portion of the wafer. Formed based on the interaction with the material of
At least one of the pulses in the pulse set has a first primary wavelength and
At least one of the other pulses in the pulse set has a second primary wavelength that is different from the first primary wavelength so that the spectra of the first and second sets of the pulses are spectrally different.
A photolithography system in which the separation distance is based on the difference between the first primary wavelength and the second primary wavelength. The control system comprises a computer-readable storage medium, one or more electronic processors coupled to the computer-readable storage medium, and an input / output interface.
The photolithography system according to claim 18, wherein the recipe related to the photolithography system is stored in the computer-readable storage medium. The photolithography system of claim 19, wherein the recipe defines the separation distance. The photolithography system according to claim 20, wherein the recipe defines the separation distance for each wafer or lot. The photolithography system of claim 18, wherein the light source comprises a krypton difluoride (KrF) gain medium or an argon fluoride (ArF) gain medium.